BoilerFaultCodesAriston L.E.D. D Fault Code
Also written as LEDD — same fault.
The Ariston L.E.D. D fault code means: your boiler has detected that water is not moving through the system properly, which is preventing it from heating up safely.. It appears on 11 Ariston models in our database.
Technical description: Circulation Failure: This control signals that the safety pressure switch on the primary circuit has not sensed a pressure of at least 1 bar within 40 seconds of the activation of the circulation pump.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is below 1 bar, use the filling loop underneath the boiler to top up the water levels.Ensure all radiator valves and internal isolation valves are fully open to allow water to flow.Reset the boiler once the correct pressure is reached.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ariston models that show the L.E.D. D fault code
Click a model for the full fault code list and model-specific repair notes.
- Challenger 80E Repair: £120-250
- E-Combi One Repair: £120-250
- E-Combi One 30 Repair: £120-250
- Euro Combi 30 MFFI Repair: £100-£280
- Euro Prisma 24 Repair: £100-280
- Genus 27 Repair: £80-150
- Genus 30 Plus Repair: £120-250
- Genus One 24 Repair: £100-250
- Genus One 30 Repair: £100-250
- Genus Premium Repair: £80-150
- Microsystem 15 Repair: £120-250
Source
Ariston L.E.D. D fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026